<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>Untitled Document</title>
</head>

<body>

<?php
if(isset($_POST["submitted"]))
{
	if(!isset($_POST["agree"]))
	{
		echo "Trebuie sa selectezi";
	}
	if(isset($_POST["agree"]))
	{
		echo "Ai selectat";
	}
}

?>

<form method="post" action="test_pg.php">
<input type="checkbox" name="agree" value="box"/>
<input type="submit" name="submit" value="submit" />
<input type="hidden" name="submitted"  value="TRUE"/>
</body>
</html>
